The dental flosses formed by multiple filaments that are held together as a strand during their manual application in the interdental spaces are well known in the prior art. With the friction movement of the floss against the proximal walls of the teeth, the different filaments are progressively disaggregated or separated from one another, promoting a greater capacity of removing the food residues by the dental floss.
These multifilaments are held together until they are rubbed in the interdental spaces. Although they are widely used and easy to insert in the interdental spaces these multifilament dental flosses have the inconvenience of allowing the separation or disaggregation of the multifilaments during the rubbing or scraping operation in the dental surfaces, causing discomfort to the user, which shall be as great as the indentations of the user's teeth.
In addition to the inconvenience above, these multifilament dental flosses require the provision of relatively high amounts of binding agents. However, excessive amounts of binding agents may impair, at a higher or lower degree, the pliability characteristic of the flosses during the application in the interdental spaces, and they also require more raw materials per length unit.
Another construction of these interdental supplementary cleaning elements is defined by the known dental tapes, of rectangular cross-section, formed by a monofilament generally obtained from a film extruded from plastic material, such as polyolefin, polyamide, polyester and fluoropolymers such as polytetrafluoroethylene (PTFE). Because they are monofilament and, therefore, united, these tapes do not have the inconvenience of tending to separate or fray when rubbed in the interdental spaces.
The known monofilament dental tapes have a smaller surface area in comparison to the interstitial surface area of the multifilament dental flosses. The smaller surface area reduces the capacity or efficacy of removing the biofilm and residues from the interdental spaces. Also, the reduced surface area, in interstitial terms, of these known monofilament dental tapes, reduces their capacity of aggregating binding agents to operate as vehicles for the incorporation of additives with abrasive, bactericide, flavoring functions, etc. In addition, because they are smooth, these monofilament dental tapes have grasping characteristics that are still poor and do not provide the user with the feeling that they are properly retained in the fingers during flossing.
The known monofilament dental tapes, with a smooth surface, have the characteristic of accepting only relatively reduced amounts of binding agents, in the form of light surface coatings consisting of, for example, different waxes having known gripping enhancing properties. The restrictions imposed by said smooth monofilament tapes to the amount of binding agents to be used in the formation of the surface coating lead to undesirable limitations in the amount of additional additives, with different active functions, such as flavoring, abrasive, bactericide, etc., to be carried by the binding agent.
A smooth dental floss having a friction enhancing wax-based surface coating, for example microcrystalline wax, to increase the gripping of the dental floss and also to operate as a carrier for different additives having active functions, is disclosed in U.S. Pat. No. 5,209,251. In such smooth dental flosses, particularly in monofilament dental flosses, the surface coating made of a binding agent is fundamental to allow imparting to the dental floss adequate gripping and also a desired capacity of rubbing and removing residues by means of additives having abrasive function, carried by the surface coating. The limitations in the amount of binding agent that can be stably incorporated to the tape undesirably restrict the efficiency of the surface coating in its function as a carrier of additives with active functions.
U.S. Pat. No. 4,646,766 (the '766 patent) discloses a dental tape constituted by a certain length of a monofilament of incipiently/slightly fibrillatable plastic film obtained from, e.g. a polypropylene film. Such films are coherent films that fibrillate spontaneously on rubbing against the surface of a tooth, and include films that have already been fibrillated and rendered temporarily stable. In this constructive solution, described in the '766 patent, the embossing operation to which the plastic tape is subjected is defined and adjusted with the purpose to provide the tape with the property to fibrillate or disaggregate in a reduced and pre-determined level, when subjected to the friction in the interdental spaces. Although such fibrillation increases the capacity of removing biofilm (plaque) and residues, such fibrillation inside the interdental spaces contribute to discomfort by the user.
In addition to the inconvenience related to the fibrillation, this prior art polymeric tape has the same disadvantages mentioned before regarding the monofilament tapes, as regard their limitations in the amount of surface binding agent which can be adequately and stably incorporated to the tape, in order to act as a gripping enhancing means and also as a carrier for additives with abrasive, flavoring, bactericide functions, etc.
U.S. Pat. No. 5,657,779 describes a method and a device to form elongated PTFE films, particularly for formation of dental tapes. The method described aims to produce a PTFE dental tape that reduces or avoids the tape fibrillation during its use and easily receives various coatings, for example, a wax carrying other additives, such as abrasives, bactericides, flavoring agents, etc. Although fibrillation is reduced during use, this prior art monofilament dental tape, with surface area limited to the cross section contour, also has the disadvantage of requiring the application of a surface binding agent to increase gripping, but in an amount which may constitute a limitation to the amount of different additives to be carried by the surface binding agent.
As noted above, while monofilament dental tapes are known, there still exists a need for monofilament dental tapes that are easily inserted into interdental spaces, provide improved gripping by the user, provide improved application and retention of additives to the tapes, with or without known binding agents, and maintain comfort by the user by avoiding fibrillation, all without compromising physical mechanical properties. The dental tapes of the present invention provide such characteristics.